Continuing Education Activity
Carpal tunnel syndrome (CTS) is an entrapment neuropathy caused by compression of the median nerve as it travels through the wrist's carpal tunnel. It is the most common nerve entrapment neuropathy, accounting for 90% of all neuropathies. Early symptoms of carpal tunnel syndrome include pain, numbness, and paresthesias. This activity reviews the etiology, presentation, evaluation, and management of carpal tunnel syndrome, and highlights the role of the interprofessional team in evaluating, and managing the condition.
Describe the pathophysiology of carpal tunnel syndrome, including triggering and exacerbating factors and activities.
Review the necessary elements for an examination to assess for carpal tunnel syndrome, including any necessary diagnostic imaging studies.
Summarize the treatment options available for carpal tunnel syndrome, including both conservative and surgical care.
Explain possible interprofessional team strategies for improving care coordination and communication to advance the evaluation and treatment of carpal tunnel syndrome and improve outcomes.
Carpal tunnel syndrome (CTS) is an entrapment neuropathy caused by compression of the median nerve as it travels through the wrist's carpal tunnel. It is the most common nerve entrapment neuropathy, accounting for 90% of allneuropathies. Early symptoms of carpal tunnel syndrome include pain, numbness, and paresthesias. These symptoms typically present,with some variability,in the thumb, index finger, middle finger, and the radial half (thumb side) of the ring finger. Painalsocan radiate up the affected arm. With further progression, hand weakness, decreased fine motor coordination, clumsiness, and thenar atrophy can occur.
In the early presentation of the disease, symptoms most often present at night when lying down and are relieved during the day. With further progression of the disease, symptoms will also be present during the day, especially with certain repetitive activities, such as when drawing, typing, or playing video games. In more advanced disease, symptoms can be constant.
Typical occupations of patients with carpal tunnel syndrome include those who use computers for extended periods of time, those who use equipment that has vibration such as construction workers, and any other occupation requiring frequent, repetitive movement.
Carpal tunnel syndrome results from increased carpal tunnel pressure and subsequent compression of the median nerve. The most common causes of carpal tunnel syndromeinclude genetic predisposition, history of repetitive wrist movementssuch as typing, or machine work as well as obesity, autoimmune disorders such as rheumatoid arthritis, and pregnancy.
The majority of CTS cases are idiopathic. Secondary CTS causes are divided into abnormalities of the container or content. Dynamic CTS can occur with manual work.
Secondary Carpal Tunnel Syndrome
Abnormalities of the Container -Any condition that modifies the walls of the carpal tunnel may cause compression of the median nerve
Dislocation or subluxation of the carpus
Fractures or skewed consolidation of the distal radius
Wrist arthrosis, inflammatory arthritis,infectious arthritis
Abnormalities of Content
Inflammatory rheumatism,and infection
Diabetes mellitus(abnormality of collagen turnover), primary or secondary amyloidosis (chronic hemodialysis with deposition of beta-2-microglobulin),and go
Abnormalities of fluid distribution: pregnancy,hypothyroidism,and chronic kidney failure (arteriovenous fistula)
Arterial hypertrophy of the median nerve
Intratunnel tumor: lipoma, synovial cyst, synovial sarcoma, or neural tumor (schwannoma, neurofibroma, or lipofibroma)
Hematoma due to hemophilia,anticoagulant accidentor trauma
Dynamic Carpal Tunnel Syndrome -The pressure inside the carpal tunnel increases during the wrist's repetitive extension and flexion movements.This particular movement can be seen in occupational pathological conditions.
Exposure to Vibration -Exposure to vibration causesultrastructural consequences that comprise microcirculatory compression problems and intraneural edema following an injury of the myelin and axons.
In the UnitedStates, carpal tunnel syndrome (CTS) has an incidence of 1 to 3 persons per 1000 per year, with a prevalence of 50 per 1000, with similar incidence and prevalence in most developed countries.
It most commonly affects Whites. Whites are two to three times more prone to get affected than Blacks.
The peak age of CTS occurrence is 40-60 years.
CTS is ten times more common in females as compared to males.
Carpal tunnel syndrome does not cause mortality, but it can lead to irreversible median nerve damage, with severe loss of hand function, if not treated.
Carpal tunnel syndrome (CTS) is multifactorial and often results from multiple patient-specific, occupational, social, and environmental risk factors. A single, specific causeis not alwaysdeterminedunless thereis, for example, a space-occupying lesionthatcan be attributable topatient-reported symptoms. While this canbe appreciated inselect medical conditions (e.g., gout),these relatively straightforward clinical presentationsarerelatively uncommonin comparison to mostpresentations of CTS.
In general, the pathophysiology of CTS results from a combination of compression and traction mechanisms. The compressive element of the pathophysiologyincludes a detrimentalcycle of increased pressure, obstruction of overall venous outflow, increasing local edema, and compromise to the median nerve's intraneural microcirculation. Nerve dysfunction becomes compromised, and the structural integrity of the nerve itself further propagatesthe dysfunctional environment - the myelin sheath and axon develop lesions, and the surrounding connective tissues become inflamed and lose normal physiologic protective and supportive function. Repetitive traction and wrist motion exacerbate the negative environment, further injuring the nerve. In addition, any of the nine flexor tendons traveling through the carpal tunnel can become inflamed and compress the median nerve.Sensory fibers often are affected before motor fibers. Autonomic nerve fibers carried in the median nerve also may be affected.
History and Physical
Patients often report numbness, tingling, and pain that increaseat night. Weakness, clumsiness, and temperature changes also are common complaints.The thumb, second and third digits, and the radial half of the fourth digit are typically affected. Symptoms are intermittent and are associated with activities like driving, reading the newspaper, and painting. Nighttime symptoms are more specific to CTS, especially if the patient relieves symptoms by shaking the hand/wrist. Bilateral CTS is common, but the dominant hand is usually affected first.Numbness predominantly in the fifth digit or extending to the thenar eminence or dorsum of the hand should suggest other diagnoses.
The clinical physical exam may include testing for sensory and motor deficits and evidence of thenar wasting. There are several special tests with varying degrees of sensitivities and specificities.
Abnormalities in sensory modalities are usually present on the palmar aspect of the first three digits and radial one-half of the fourth digit. Sensory examination is most useful in confirming that thenar eminence, hypothenar eminence, and the dorsum of the first web space are normal.
Wasting and weakness of first and second lumbricals, opponens pollicis, abductor pollicis brevis, and flexor pollicis brevis.
Hoffmann-Tinel sign -Although a low sensitivity and specificity, the Hoffmann-Tinel sign is another test commonly performed. In this test the healthcare professional taps immediately over the carpal tunnel to stimulate the median nerve. Like the above tests, a positive test is when symptoms are reproduced.
The carpal compression test - The carpal compression test is the best test. This is done by applying firm pressure directly over the carpal tunnel for 30 seconds. The test is positive when paresthesias, pain, or other symptoms are reproduced.
Phalen sign - The Phalen test or ‘reverse prayer’ is performed by having the patient fully flex their wrists by placing dorsal surfaces of both hands for one minute. A positive test is when symptoms (numbness, tingling, pain) are reproduced.
Reverse Phalen test - The reverse Phalen, or ‘prayer test,’ is done by having the patient extend both of their wrists by placing palmar surfaces of both hands together for one minute (as if praying). Again a positive test is with the reproduction of symptoms.
Palpatory diagnosis - Another test is a palpatory diagnosis. In this test, the health care provider examines soft tissue over the median nerve for mechanical restriction.
The square wrist sign - The square sign test is an evaluation to determine the risk of developing carpal tunnel syndrome. The test is positive if the ratio of the thickness of the wrist divided by the width of the wrist is great than 0.7.
There is no blood test that could help in the diagnosis of carpal tunnel syndrome.
Magnetic Resonance Imaging (MRI)
MRI of the carpal tunnel is particularly useful preoperatively if a space-occupying lesion in the carpal tunnel is suggested.MRI is a resource-intensive investigation and does not rule out other differential diagnoses.
Ultrasonography potentially can identify space-occupying lesions in the carpal tunnel. It can also detect abnormalities in the median nerve like an increased cross-sectional area that can be diagnostic of CTS. Ultrasonography can also help to guide steroid injections into the carpal tunnel.
Electromyographyand Nerve Conduction Studies
Electromyographyand nerve conduction studies are the basis for carpal tunnel syndrome diagnosis. Other clinical or special exams do not confirm carpal tunnel syndromebut doassist in ruling out other diagnoses. These findings can prompt electromyography and nerve conduction studies.Abnormalities on electrophysiologic testing, in association with specific symptoms and signs, are considered the gold standard for CTS diagnosis. Electrophysiologic testing also can assess the severity of the damage to the nerve and also determine prognosis. CTS is usually divided into mild, moderate, and severe. In mild CTS patients have sensory abnormalities alone on electrophysiologic testing, and in moderate CTS patients have sensory plus motor abnormalities.
Treatment / Management
If carpal tunnel syndromeis identified early, conservative treatment is recommended.
Physical and Occupational Therapy
Initially, the patient should be instructed in modifying symptom provoking wrist movement. This can be through proper hand ergonomics such as placing the keyboard at a proper height and minimizingflexion, extension, abduction, and adduction of the handwhen typing. It should be recommended to decrease repetitive activities if possible. Counseling on weight loss and increased aerobic activityalsocan be beneficial. A properly fitted nighttime wrist splint can be offered. An occupational therapist trained in hand therapyalsomay be a beneficial referral. Combined therapy may be more beneficial than any single treatment. A short course of nonsteroidal anti-inflammatory medication can relieve symptoms but some do not feel it of adequate benefit.
Patients with mild to moderate carpal tunnel syndrome respond to conservative management, which includes splinting the wrist at nighttime for at least three weeks. If conservative treatment fails, a steroid injection into the carpal tunnel can be beneficial.Steroid injections may also be beneficial before surgical management or when surgery is relatively contraindicated as in pregnancy.Median nerve measurements by ultrasound can predict response to steroid injection.
Nonsteroidal anti-inflammatory drugs (NSAIDs) may be useful against CTSin patients with wrist flexor tendinitis. Similarly, diuretics can be helpful in patients with fluid overload.gabapentin and pregabalin, which are used in different types ofneuropathic pain, can be used, forCTS off-label. The American Academy of Orthopaedic Surgeons state thatoral agentsare no better than placebo in the treatment of CTS.
Patients who do not get better following conservative treatment and those who have severe carpal tunnel syndrome as defined by electrophysiologic testing should be considered for surgery. The definitive treatment for persistent carpal tunnel syndromeis a surgical intervention with carpal tunnel release after nerve conduction studies showing significant axonal degeneration. Carpal tunnel releasetypicallyis performed by a neuro/orthopedic/plastic surgeon or hand surgeon. This procedure can be performed either open or endoscopically. Carpal tunnel release is considered a minor surgery in which the transverse carpal ligament or flexor retinaculum is cut, opening more space in the carpal tunnel and decreasing pressure on the median nerve. It does not typically require overnight hospitalization.Surgical release of the transverse ligament gives greater than 90% initial success rate, and low rates of complication. However, it has been found in different trials that the long-term success rate is lower than initially thought (approximately 60% at 5 years).
Guidelinesby the American Academy of Orthopaedic Surgeons
The American Academy of Orthopaedic Surgeons released guidelines on the management of CTS. Following recommendations were made:
Thenar atrophy is strongly associated with ruling in CTS but is poorly associated with ruling it out
Phalen test, Tinel sign, flick sign, or upper limb neurodynamic/nerve tension test (ULNT) criterion A/B should not be used as independent physical examination maneuvers to diagnose CTS, because alone, each has a poor or weak association with ruling in or ruling out the condition
Independent history interview topics should not be used to diagnose CTS, because alone, each has a poor or weak association with ruling in or ruling out the condition: sex/gender, ethnicity, bilateral symptoms, diabetes mellitus, worsening symptoms at night, duration of symptoms, patient localization of symptoms, hand dominance, symptomatic limb, age, and body mass index
Magnetic resonance imaging (MRI) should not be a routine for the diagnosis of CTS
Diagnostic questionnaires and/or electrodiagnostic studies can be used to aid the diagnosis of CTS
The following factors are associated with an increased risk of developing CTS: peri-menopausal, wrist ratio/index, rheumatoid arthritis, psychosocial factors, distal upper extremity tendinopathies, gardening, assembly line work, computer work, vibration, tendonitis, workplace forceful grip/exertion
Physical activity/exercise is associated with a decreased risk of developing CTS
The use of immobilization (brace/splint/orthosis) should improve patient-reported outcomes
The use of steroid (methylprednisolone) injection should improve patient-reported outcomes
There is no benefit to oral CTS treatments (diuretic, gabapentin, astaxanthin capsules, nonsteroidal anti-inflammatory drugs [NSAIDs], or pyridoxine) over placebo
Oral steroids could improve patient-reported outcomes in comparison with placebo
The surgical release of the transverse carpal ligament should relieve CTS symptoms and improve function
Surgical treatment of CTS should have a greater therapeutic benefit at 6 and 12 months in comparison with splinting, NSAIDs/therapy, and a single steroid injection
There is no benefit to routine postoperative immobilization after carpal tunnel release
The presentation of carpal tunnel syndrome mimics many other disorders of the musculoskeletal and nervous systems. Following differentials should be considered while assessing a patient with carpal tunnel syndrome:
Cervical disc disease
Cervical myofascial pain
Traumatic brachial plexopathy
Radiation-induced brachial plexopathy
Thoracic outlet syndrome
Carpal tunnel syndrome (CTS) is usually progressive over time and can cause permanent median nerve damage. The syndrome recurs to some degree even after surgical management in up to one-third of the patients after 5 years. Almost 90% of mild to moderate CTS cases respond to conservative management. However, many patients progress to requiring surgery. Patients with CTS secondary to diabetes or wrist fracture tend to have a less favorable prognosis than do those with no apparent underlying cause. Patients who have normal electrophysiologic studies have much less favorable operative outcomes than do individuals with abnormalities on these tests and also more complications. Axonal loss on electrophysiologic testing is also a poor prognostic factor.
Complications of carpal tunnel syndrome are divided into two groups:
Complications due to Carpal Tunnel Syndrome
Carpal tunnel syndrome may cause irreversible median nerve damage, leading to permanent impairment and disability.
Chronic wrist and hand pain with or without reflex sympathetic dystrophy.
CTS can cause atrophy and weakness of the muscles at the base of the thumb in the palm of the hand. This can lead to a lack of dexterity of the affected fingers.
Complications due to Carpal Tunnel Surgery
The most frequent complication is neuroma of the palmar cutaneous branch of the median nerve.
Dysesthesias after multiple procedures to release the carpal tunnel
Wrist Joint stiffness
Failure to relieve symptoms
Deterrence and Patient Education
Patients suffering from carpal tunnel syndrome should be educated about the nature of the disease, precautions that they need to take, and rehabilitative activities. These include:
Avoid repetitive hand motions, holding onto vibrating tools, heavy grasping and positioning, or working with your wrist bent down and out.
Lose weight if overweight
Reduce caffeine intake
A wrist bracewill sometimes decrease the symptoms. A brace keeps the wrist in a resting position, not bent back or bent down too far. A brace can be especially helpful for relieving the numbness and pain felt at night because it can keep your hand from curling under as you sleep. The wrist brace can also be worn during the day.
Consult with a physical or occupational therapist. Therapist may check the workstation and the way the patient does his/her work tasks. Therapist would give suggestions regarding the use of healthy body alignment and wrist positions, helpful exercises, and tips on how to prevent future problems.
Pearls and Other Issues
The carpal tunnel includes the median nerve and nine flexor tendons. The flexor tendons include the four tendons from the flexor digitorum profundus, four tendons from the flexor digitorum superficialis, and one tendon from the flexor pollicis longus. The transverse carpal ligament (flexor retinaculum)makes up the superior boundary, and the carpal bonesform theinferior border.
Enhancing Healthcare Team Outcomes
The diagnosis and management of carpal tunnel syndrome are done with an interprofessional team that includes the primary care provider, nurse practitioner, physical therapist, neuro/orthopedic/plastic surgeon, and the emergency department provider. The initial treatment is usually conservative combined with limiting repetitive activities. A properly fitted nighttime wrist splint can be offered. An occupational therapist trained in hand therapyalsomay be a beneficial referral. Combined therapy may be more beneficial than any single treatment. A short course of nonsteroidal anti-inflammatory medication can relieve symptoms but some do not feel it is of adequate benefit.
Many other treatments are available to treat carpal tunnel syndrome including surgery. An orthopedic specialty nurse can assist at all phases of care, regardless of whether treatment is conservative or surgical. While surgery can relieve symptoms, recurrence is not uncommon. The patient must be fully educated about the potential complications of surgery which should only be undertaken after conservative treatments have failed. An interprofessional team approach will lead to better outcomes for patients with CTS. [Level 5]
Untreated Carpal Tunnel Syndrome. Contributed by Wikimedia Commons, Dr. Harry Gouvas, MD, PhD (Public Domain)
Carpal tunnel syndrome. Image courtesy S Bhimji MD
Physical exam maneuvers that test for carpal tunnel syndrome. Contributed by Rian Kabir, MD
Mezian K, Bruthans J. Why do local corticosteroid injections work in carpal tunnel syndrome, But not in ulnar neuropathy at the elbow? Muscle Nerve. 2016 Aug;54(2):344. [PubMed: 27144462]
Maher AB. Neurological assessment. Int J Orthop Trauma Nurs. 2016 Aug;22:44-53. [PubMed: 27118633]
Akhondi H, Varacallo M. StatPearls [Internet]. StatPearls Publishing; Treasure Island (FL): Sep 4, 2022. Anterior Interosseous Syndrome. [PubMed: 30247831]
Sevy JO, Varacallo M. StatPearls [Internet]. StatPearls Publishing; Treasure Island (FL): Sep 5, 2022. Carpal Tunnel Syndrome. [PubMed: 28846321]
Hegmann KT, Merryweather A, Thiese MS, Kendall R, Garg A, Kapellusch J, Foster J, Drury D, Wood EM, Melhorn JM. Median Nerve Symptoms, Signs, and Electrodiagnostic Abnormalities Among Working Adults. J Am Acad Orthop Surg. 2018 Aug 15;26(16):576-584. [PubMed: 30028751]
Pester JM, Bechmann S, Varacallo M. StatPearls [Internet]. StatPearls Publishing; Treasure Island (FL): Sep 4, 2022. Median Nerve Block Techniques. [PubMed: 29083641]
Tai TW, Wu CY, Su FC, Chern TC, Jou IM. Ultrasonography for diagnosing carpal tunnel syndrome: a meta-analysis of diagnostic test accuracy. Ultrasound Med Biol. 2012 Jul;38(7):1121-8. [PubMed: 22542258]
Marshall S, Tardif G, Ashworth N. Local corticosteroid injection for carpal tunnel syndrome. Cochrane Database Syst Rev. 2007 Apr 18;(2):CD001554. [PubMed: 17443508]
Eftekharsadat B, Babaei-Ghazani A, Habibzadeh A. The Efficacy of 100 and 300 mg Gabapentin in the Treatment of Carpal Tunnel Syndrome. Iran J Pharm Res. 2015 Fall;14(4):1275-80. [PMC free article: PMC4673958] [PubMed: 26664397]
Sears ED, Swiatek PR, Hou H, Chung KC. Utilization of Preoperative Electrodiagnostic Studies for Carpal Tunnel Syndrome: An Analysis of National Practice Patterns. J Hand Surg Am. 2016 Jun;41(6):665-672.e1. [PMC free article: PMC4899197] [PubMed: 27068003]
Mooar PA, Doherty WJ, Murray JN, Pezold R, Sevarino KS. Management of Carpal Tunnel Syndrome. J Am Acad Orthop Surg. 2018 Mar 15;26(6):e128-e130. [PubMed: 29420323]
Raizman NM, Blazar PE. AAOS Appropriate Use Criteria: Management of Carpal Tunnel Syndrome. J Am Acad Orthop Surg. 2018 Mar 15;26(6):e131-e133. [PubMed: 29432365]
Carmona A, Hidalgo Diaz JJ, Facca S, Igeta Y, Pizza C, Liverneaux P. Revision surgery in carpal tunnel syndrome: a retrospective study comparing the Canaletto® device alone versus a combination of Canaletto® and Dynavisc® gel. Hand Surg Rehabil. 2019 Feb;38(1):52-58. [PubMed: 30472072]
Eroğlu A, Sarı E, Topuz AK, Şimşek H, Pusat S. Recurrent carpal tunnel syndrome: Evaluation and treatment of the possible causes. World J Clin Cases. 2018 Sep 26;6(10):365-372. [PMC free article: PMC6163139] [PubMed: 30283799]